import numpy as np
import pandas as pd
arr = np.random.randint(1,20, size=(3,3))
df = pd.DataFrame(arr,columns=['c','b','a'])
print('原始数据:\n',df)
print('按列索引降序排序\n',df.sort_index(ascending=False))
print('按列索引降序排序\n',df.sort_index(axis=1))
